docs: fix 12 verified doc-vs-code inaccuracies

[jkyberneees]

Summary

Fixes 12 verified documentation inaccuracies (13 edits across 9 files) where the docs contradicted the code. Every finding was confirmed against source before editing; every "candidate" that turned out to be accurate was left alone.

Findings

Doc	Wrong	Correct
docs/CONFIG.md	ODEK_MAX_TOOL_PARALLEL env var (env table + settings table)	No such env var, and no generic ODEK_* mapper — proven with a probe test (ODEK_MAX_TOOL_PARALLEL=7 → MaxToolParallel = 0)
docs/CONFIG.md	Pinned-keys note referenced stream: true	Sample config has no stream key
docs/MEMORY.md	Subagents inherit a read-only facts snapshot via odek subagent --memory-snapshot <file>	No such flag; subagents read the shared ~/.odek/memory store
docs/MEMORY.md	Prompt header # Memory Context (read-only)	Real header ═══ MEMORY [N% — X/Y chars] ═══
docs/MEMORY.md	"Subagents do NOT get a memory tool"	Registered under the same tools filter; tools.disabled is the control
docs/MEMORY.md	--interaction verbose	--interaction-mode verbose
docs/SECURITY.md	--sandbox-volume flag	sandbox_volumes config key
docs/MIGRATION.md	--api-key CLI flag	Only ODEK_API_KEY exists
docs/TOOL_SELECTION.md	--continue flag	odek continue subcommand
docs/TELEGRAM.md	default_chat_id env var blank	ODEK_TELEGRAM_DEFAULT_CHAT_ID
docs/WEBUI.md	"simplex prompt → stream → done flow"	Bidirectional — doc itself documents cancel, subagent_cancel, ping, approval_response, session_switch
docs/SESSIONS.md	Programmatic API snippet imported internal/session with no caveat	Marked in-module only, with the public-API pointer
AGENTS.md	-run "TestMCPE2E_"	-run "TestMCPClientE2E_"

Verification

• Per-finding assertion gate (stale text absent, corrected text present) — exit 0
• Doc scanner: 154 links, 0 broken; no missing repo paths; every referenced Go symbol exists
• go build ./... + go vet ./... — OK

Out of scope (reported, not changed)

• Makefile test-cmd skip pattern TestMCPE2E does not match TestMCPClientE2E_* — harmless today (those tests self-skip without ODEK_E2E). Not a doc issue.
• RunWithMessages takes []session.Message (internal), so the session-oriented API is unreachable from external modules; a type Message = session.Message alias would close it. Separate decision.