feat(profiles): add session profile v1 record decoder

[noxsystems]

Review size: this slice adds 370 changed lines (+370/-0): 131 module, 203 tests, 36 docs. Review commits 820318794 and 67868a9ac.

Summary

Part of #1064, slice 3b-i (persistence codec). First of two pure PRs: the v1 record format and its decoder only. No consumer reads it yet, so Enter, startup, routing, shared defaults and the live orchestrator do not change.

• Record format: custom entry gentle-pi.session-profile/v1 with a bind payload (origin, name, modelProfiles) or a minimal clear.
• Decoder readSessionProfileEntry: closed origin set user | local | repo | global; required fields checked as own properties, so prototypes cannot supply them; one invalid route invalidates the whole snapshot instead of silently dropping it; unknown payload and route fields carry no meaning; hostile keys (__proto__, constructor) stay own data on a plain object; family identifier decides unsupported, payload version does not.
• Results: absent | bound | cleared | invalid | unsupported. A bound empty snapshot is not a clear.
• Reuses the existing agent-profiles name policy and model-routing-authority normalization (legacy model strings and effort, thinking wins).

This is PR 1 of 2.

Issue

Part of #1064

PR type

• New feature (type:feature)

Changes

Commit	Change
820318794	lib/session-profile-persistence.ts (decoder), tests/session-profile-persistence.test.ts, docs/session-profile-format.md.
67868a9ac	Export isSafeAgentName from lib/model-routing-authority.ts and use it in the decoder; constructor/prototype own-data assertions (CodeRabbit).

Test plan

On main 9782d26df, Node 25.2.1:

• node --experimental-strip-types --test-reporter=tap --test tests/session-profile-persistence.test.ts: 13 pass, 0 fail.
• tests/agent-profiles.test.ts + tests/model-routing-authority.test.ts: 59 pass, 0 fail (shared helpers unchanged).
• node scripts/check-types.mjs: 186 recorded diagnostics, no regressions (count ratchet, not clean tsc).
• Native review (RDD): not run on this slice.

Review follow-ups

• Addressed in 67868a9ac: readSnapshot now uses the exported isSafeAgentName predicate instead of probing normalizeModelConfig.

Chain Context

Field	Value
Chain	#1064 slice 3b-i: session profile persistence codec
Tracker PR	Not needed
Position	1 of 2
Base	main (fork PRs cannot stack bases; PR 2 shows this commit until it merges)
Depends on	nothing
Follow-up	PR 2: encoder + active-branch replay; then #1922 disk corroboration; later: Enter wiring (composition agreed with @danielgap on the issue, #1824 keeps the live orchestrator and s)
Review budget	370 changed lines, of which 203 are tests and 36 docs.

main
 └─ PR 1 decoder: record format, readSessionProfileEntry       📍 this PR
   └─ PR 2 encoder + replaySessionProfileBranch
     └─ #1922 readSessionProfileDisk: on-disk corroboration
       └─ (later) append controller, authority, Enter persistence wiring

Summary by CodeRabbit

• New Features
  • Added support for decoding optional version 1 session profile records, including profile bindings and clear entries. Existing runtime behavior is unchanged.
• Documentation
  • Documented supported record types and origins, validation and normalization rules, and current limitations. Startup persistence, follow mode, encoding, and active-branch replay are not supported.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: Repository UI
• Review profile: ASSERTIVE
• Plan: Advanced
• Run ID: 4aa777b4-a134-494c-96ae-566c0da06159

📥 Commits

Reviewing files that changed from the base of the PR and between 8203187 and 67868a9.

📒 Files selected for processing (3)

• lib/model-routing-authority.ts
• lib/session-profile-persistence.ts
• tests/session-profile-persistence.test.ts

Included review availability: This review used your included allowance. Your plan provides up to 4 included reviews per hour; 0 remain after this review.

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📝 Walkthrough

Walkthrough

The pull request adds a standalone decoder for session-profile v1 entries. It validates and normalizes binding data, classifies entry outcomes, adds decoder tests, and documents the format.

Changes

Session profile decoding

Layer / File(s)	Summary
Validate and normalize profile payloads lib/session-profile-persistence.ts, tests/session-profile-persistence.test.ts	Adds payload types and validation for origins, names, model-profile snapshots, and routes. Tests cover accepted and rejected payloads, normalization, and detached snapshots.
Classify entries and document the format lib/session-profile-persistence.ts, tests/session-profile-persistence.test.ts, docs/session-profile-format.md	Classifies entries as absent, unsupported, invalid, cleared, or bound. Tests cover entry classification, and documentation describes the v1 payloads and decoding outcomes.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Feature

Merge Risk: ⚪ Minimal · up to 67868

This change adds a decoder whose behavior matches its documented format, with focused coverage for invalid inputs and hostile keys. No actionable merge-blocking risk was identified; normal checks still apply.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 30.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 10 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: adding a session profile v1 record decoder.

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Actionable comments posted: 2

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• 🪄 Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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Inline comments:
Review comments at @lib/session-profile-persistence.ts:
- Around line 93-94: Update name validation in readSnapshot to use the shared
isSafeAgentName predicate instead of constructing a temporary config with
normalizeModelConfig; retain the existing rejection behavior for names that fail
the shared policy.

Review comments at @tests/session-profile-persistence.test.ts:
- Around line 145-160: Update the test “hostile record keys remain own data
without changing prototypes” to assert that `constructor` and `prototype` are
preserved as own properties with their expected values, in addition to the
existing `__proto__` assertions.

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ℹ️ Review info

⚙️ Run configuration

• Configuration used: Repository UI
• Review profile: ASSERTIVE
• Plan: Advanced
• Run ID: 3684f0c4-855d-4836-bd3c-7a4df295f60d

📥 Commits

Reviewing files that changed from the base of the PR and between 9782d26 and 8203187.

📒 Files selected for processing (3)

• docs/session-profile-format.md
• lib/session-profile-persistence.ts
• tests/session-profile-persistence.test.ts

Included review availability: This review used your included allowance. Your plan provides up to 4 included reviews per hour; 3 remain after this review.

[noxsystems]

Both CodeRabbit comments addressed in 67868a9ac: isSafeAgentName is now exported from lib/model-routing-authority.ts and used by the decoder (the normalizeModelConfig probe is gone), and the hostile-keys test asserts constructor and prototype stay own data. #1919 and #1922 are rebased on top.