feat(timeline): month-by-month timeline page, synced with GitHub profile README

[TimeToBuildBob]

Adds a /timeline/ page and makes it the source of truth for the GitHub profile README.

• _data/timeline.yml: one entry per month from Nov 2024 to Sep 2026. Each has a one-line summary, public merged-PR count and 4–8 highlights with links. All links were checked with gh api and point only to public repos (merged PRs or releases). Quiet stretches can use a single end: range entry.
• timeline.pug: renders the data grouped by year with jump links and per-month anchors. Also adds a nav link.
• scripts/render_profile_readme.py: renders the three most recent months in full, then one visible line per month grouped by year, with each year's full detail in a <details> fold. The output replaces the <!-- timeline:start/end --> block in the profile README, and --check exits 1 when that block is stale. Tests are in tests/test_render_profile_readme.py.

The profile repo side is a daily sync-timeline workflow that sparse-checks-out this data file and the renderer. That lands in a companion PR on TimeToBuildBob/TimeToBuildBob. Merge this PR first.

Verified locally: pytest passes (9/9), the Jekyll build passes, and /timeline/ renders all 16 entries.

[TimeToBuildBob]

🤖 AI code review

Adds a /timeline/ page backed by a new _data/timeline.yml source-of-truth file, a nav link in the default layout, and a Python script that renders the timeline data into the GitHub profile README between timeline:start/end markers, with tests for the renderer.

Safe to merge — no P0/P1 findings

Confidence 5/5

✅ No findings. The diff looks correct to me on this pass.

Files changed (6) — the diff as I read it

• README.md — Adds a Timeline link to the site index and a 'Timeline: Source of Truth' section describing the sync flow from _data/timeline.yml.
• _data/timeline.yml — New YAML data file with per-month entries, year summaries, PR counts, highlights, and range entries for quiet stretches.
• _layouts/default.pug — Adds a 'Timeline' navigation link to the site header.
• scripts/render_profile_readme.py — New Python script that renders the timeline YAML into a README block between timeline:start/end markers, with --check mode.
• tests/test_render_profile_readme.py — New pytest tests covering render output, label formatting, splice idempotence, check mode, and real data validity.
• timeline.pug — New Jekyll page template that renders the timeline data grouped by year with jump links and per-month anchors.

Previous review passes

commit	score	findings	engine	when
bb34cc365ee2	4/5	1	llm	2026-09-14 08:20 UTC

_{Reviewed 47e5a9559401 · openrouter/deepseek/deepseek-v4-flash-0731 · llm engine · 42s · about this reviewer}

_{Maintainer commands}

_{@TimeToBuildBob review (own line) — fresh review · @TimeToBuildBob fix — a worker acts on the findings. Once per comment; 👀 = received.}

[TimeToBuildBob]

Re-reviewed current head 47e5a955 — 5/5, 0 findings. The P2 (--recent 0 swallowed by or) was already fixed in a493ba6.

Self-merge not eligible here (root README.md is spec-like; repo is outside the workspace allowlist). Waiting for human review or merge.

Companion TimeToBuildBob/TimeToBuildBob#10 depends on this landing first.