fix: read the repository-docs index by header name, not by column count

[hkwuks]

Summary

Fix the SessionStart:resume failure repository-document index contains an invalid row — reported on resume, and reproduced against this hook's own output.

The reader required 6–8 cells and a backticked path cell, so any index written by an earlier TaskFlow version was unreadable. That is the compatibility problem: the writer and the reader disagreed about a file the writer itself produces, and the failure lands in SessionStart, where it silently costs the session its entire repository routing context (the hook error is non-blocking, so it shows one line and lets you keep working).

Reproduced from a live sibling repository on this machine: its index has four columns (no Status) and unquoted paths, and it failed outright.

Changes

hooks/repository-docs-context — locate columns by the header names (Class, Source/Source path, Phases, Exists, Status) instead of by position. Every shape this repository has written now parses:

Shape	Origin
4 columns, no Status, unquoted path	an earlier shape, still live in a sibling repository
7 columns with a Last checked date	TaskFlow 1.0.8 and earlier, and this repository until 2026-09-21
5 columns	current

A path cell may or may not be backticked, and a status may be capitalized or contain a space.

Two things stay enforced. A row whose status cell holds a date is still rejected: that means the row shifted, and carrying the date over is how a malformed index would be laundered into the rendered one. With no header to read the shape from, the positional fallback still rejects a date-shaped path.

One judgement call worth flagging for review: once the header has named the columns, the path cell is no longer shape-checked as a status. A one-word path such as LICENSE is indistinguishable from a status by shape, and the first version of this patch rejected it — dropping a real repository document. The header is what makes the cell's meaning known, so the heuristic is not needed there.

hooks/smoke-test — seven assertions over the shapes above (four readable shapes, optional backticks, a tolerant status, and a shifted row still rejected). Mutated once — the old strict rules restored — to confirm they fail.

Archive 2026-09-20-windows-git-path and mark TF-20260920-9f3c07 done. Its plan and PRD were already completed and its PR (#45) merged, but the task was never archived, so the Todo entry still read Complete PRD / Spec / Plan and request approval.

TaskFlow traceability

• Task: TaskFlowDocs/achieved/2026-09-20-windows-git-path/ (archived here); the reader fix is tracked by TF-20260921-4d8ae2, whose entry records the root cause and the workaround
• Scope: hooks/repository-docs-context, hooks/smoke-test, TaskFlowDocs/todo.md, and the archive move
• Base branch: main
• Target repository: hkwuks/TaskFlow (origin)

Verification

• bash hooks/smoke-test — ALL SMOKE PASSED
• git diff --check — clean
• Relevant Skill/plugin validation — bash -n clean on both changed hooks; the affected hook is fully covered by the smoke suite; no skill or manifest file is touched, so no Skill validation is applicable
• Results recorded in the TaskFlow Plan — the archive is recorded by hooks/task complete

Beyond the suite: all four repositories on this machine (Mimir, cc-switch, Survival, TaskFlow) read their index.md successfully.

Review boundaries

• No secrets or opaque remote payloads included
• No unrelated task or user files changed
• Remote/base assumptions are stated — pushed to origin (hkwuks/TaskFlow), targeting main
• Known limitations and follow-ups are documented below

Known limitations

• Only the shapes actually found in the wild are covered. A shape nobody has written yet would still fail — the reader is tolerant, not omniscient, and the smoke assertions pin the shapes known today.
• The row is still read positionally when the header is absent. That path stays strict deliberately, but it is a guess, and a headerless index with an unusual column set could be rejected.
• TF-20260921-4d8ae2 stays open in inbox; this PR implements its fix but does not promote or close it.