docs: replace hardcoded developer paths with /path/to placeholders

[abrichr]

Follow-up to #14, which fixed the code and left the docs. This does the docs: 291 hardcoded paths across 51 markdown files.

Merge #14 first. This branch is stacked on it, so the diff here is docs plus one change to the guard test. Base will retarget to main automatically once #14 lands.

Why this isn't cosmetic

A reader who copies cd /Users/abrichr/oa/src/openadapt-viewer out of CLAUDE.md gets "no such file or directory". Same for the ls, open, cp and --results-dir examples. Those commands were already broken for everyone except one person. They just failed at the shell instead of in CI, so nobody filed it.

What the substitution does

/Users/abrichr/oa/src becomes /path/to, one for one, 292 lines in and 292 out. That placeholder isn't invented: 16 of these files already use /path/to/recording and /path/to/screenshot.png in the spots that got it right.

Paths stay absolute, so cd, open, ls, file:// URLs and the JSON examples all stay valid as templates. file:///path/to/openadapt-capture/... is still a well-formed file:// URL.

I considered rewriting the **File**: /Users/.../openadapt-viewer/foo.html references as plain repo-relative foo.html, which reads better. I didn't. That means judging context at 291 sites across 51 files I haven't read end to end, and a wrong call there quietly changes what a document claims. Mechanical and checkable beat nicer and risky at this volume. Happy to do a second pass on the highest-traffic files if you want them prettier.

Three cases the main rule missed

• /Users/abrichr/.openadapt/catalog.db is relative to home, not to the checkout, so it became ~/.openadapt/catalog.db. Rewriting it as /path/to would have been wrong.
• --waa-path /Users/abrichr/oa/WindowsAgentArena sits one level above the checkout root.
• BENCHMARK_VIEWER_ISSUES.md:34 pastes ps aux output starting with the bare account name. Same leak, no leading slash, so the path rules skipped it. Now youruser.

Guard

tests/test_no_hardcoded_paths.py drops its markdown exemption. #14 added it with .md deliberately out of scope because the docs were still dirty; they aren't now, so the exemption goes. This is the reason the branch is stacked rather than cut from main: both PRs would otherwise create the same file and conflict.

Verified by planting a violation in a root document and in docs/, on an otherwise clean tree, and confirming a clean tree passes.

#13 merged mid-way through, so both branches are rebased on it and the guard's allowlist is empty. No tracked file is exempt any more.

Result

No tracked file in the repo contains /Users/ or /home/, and the string abrichr no longer appears in any markdown.

pytest tests/ gives 145 passed, 46 skipped. ruff check . passes.

One thing I got wrong

My first pass at verifying the guard used git checkout <file> to remove a planted violation, which also discarded that file's sweep. DELIVERABLES.md (29 paths) and docs/SETUP.md (6) silently reverted. Caught it because the guard failed on what should have been a clean tree, re-applied, and switched to a copy-and-restore for the remaining checks. Worth knowing if you spot-check the diff: those two files were swept twice.