[8/9] Remove --group-by-team-prefix-consolidate and consolidateTeamHierarchy

[shouze]

Context

Issue #178 (closed by PR #185) implemented --group-by-team-prefix-consolidate / consolidateTeamHierarchy: a mode that collapses unambiguous single-branch nesting chains into one heading with an (including …) suffix.

After using this in practice, it does not match the functional need: the actual pain point is the manual effort of resolving combined/ambiguous sections (e.g. "gamme-lead-client + gamme-lead-client-p1") one by one via --pick-team, not the visual density of unambiguous single-branch chains. This option is being replaced by an automatic pick-team resolution strategy, tracked in a new sibling issue (auto-pick via smallest-common-prefix). --group-by-team-prefix-consolidate and consolidateTeamHierarchy must be removed entirely rather than kept alongside the new option.

Part of EPIC #125.

Solution

Remove the feature end-to-end, keeping shared tree helpers that other code paths still use:

• github-code-search.ts: remove the --group-by-team-prefix-consolidate CLI option definition, the groupByTeamPrefixConsolidate field on the parsed options type, the consolidateApplied computation (including its --format json stderr warning), the consolidateTeamHierarchy import/call, and the consolidateTeamSections field passed to buildReplayCommand / runInteractive.
• src/group.ts: remove consolidateTeamHierarchy and its private helper consolidateNode. Keep assignLevels and pruneEmptyChildren — both are still used by nestOverlappingLabels / groupByTeamHierarchy.
• src/group.test.ts: remove the describe("consolidateTeamHierarchy", …) block and its import.
• src/output.ts: remove consolidateTeamSections from ReplayOptions, from buildReplayCommand's destructuring/flag emission, and from runInteractive's parameter list.
• src/output.test.ts: remove the consolidateTeamSections / --group-by-team-prefix-consolidate replay-command test cases.
• src/tui.ts: remove the consolidateTeamSections parameter and its forwarding to the renderer.
• src/completions.ts + src/completions.test.ts: remove the group-by-team-prefix-consolidate completion entry and its bash/zsh/fish assertions.
• Docs: remove the "Advanced: consolidated rendering" section from docs/usage/team-grouping.md (including the JSON-ignores-consolidation warning box and the "regardless of --group-by-team-prefix-consolidate" wording nearby) and the option row from docs/reference/cli-options.md.
• CHANGELOG.md: drop "consolidated rendering" from the pending v2.0.0 entry's summary.

No replacement CLI surface is introduced by this issue — the removal is a prerequisite for the new auto-pick issue, not a rename.

Acceptance Criteria

• --group-by-team-prefix-consolidate is no longer a recognized CLI option (absent from --help, shell completions, and docs).
• consolidateTeamHierarchy and consolidateNode no longer exist anywhere in src/.
• assignLevels and pruneEmptyChildren are untouched and still used by the hierarchy-building code path.
• The replay command never emits --group-by-team-prefix-consolidate.
• docs/usage/team-grouping.md and docs/reference/cli-options.md no longer mention the option.

Definition of Done

• bun test, bun run lint, bun run format:check, bun run knip, bun run build.ts all green.
• bun run knip reports no newly-unused exports left behind by the removal.
• No functional regression to --group-by-team-prefix, automatic overlapping-name nesting, or --pick-team (all unrelated to this removal).