fix(experiments): resolve the sweep harnesses' paths, so a recorded run can be re-run

[eaitbrahim]

What

Four sweep harnesses in docs/experiments/ hardcoded two absolute paths — the deployment DB under one laptop's home, and an output dir inside a per-session temp directory that is collected when that session ends. Both now resolve, and both are overridable:

DB      = $KEEL_EXPERIMENT_DB  or ~/keel/keel.db
OUT_DIR = $KEEL_EXPERIMENT_OUT or <script dir>/_out

The default DB resolves to the same physical file it named before, so nothing changes on the machine these were written on — it just stops being the only machine where they work.

Why it matters more than it looks

A recorded experiment that cannot be re-run is the one thing a recorded experiment must not be, and the output path had already gone stale.

_out/ is gitignored but deliberately not temporary: these sweeps are resumable, reading their own append-only JSONL back to skip completed cells, so that file has to outlive the run. A per-session scratch dir is exactly what broke that.

It is also the handoff point between scripts — each *-rsi-scale run reads the JSONL its matching *-intersection run writes, as the ANCHOR supplying its oversold=20 rows. Both chains verified by name, and the two studies verified not to collide (intersection.jsonl vs intersection_257.jsonl).

Only half of this was lintable

Ruff saw two of the four files. The other two spelled the dead path as a multi-line SCRATCH constant — under the line limit, so flagged by nothing. They were found by grepping for the literal rather than trusting the linter's list. The hardcoded DB was invisible to ruff in all four.

Lint cleanup

Also clears the 13 remaining ruff findings under docs/: 6 import blocks (autofix) and 5 long lines rewrapped without changing any output; the other 2 were the path literals above.

ruff check . now passes repo-wide — previously only the CI-scoped ruff check keel tests packages did.

Verification

• Candles load through the resolved DB path: 44,407 bars for BTC-USD, matching the ~44k those docstrings cite. Run against a copy of the live DB, not the deployment file.
• Defaults and both env overrides assert-checked, including that the output dir gets created.
• ANCHOR chain confirmed intact for both study pairs.
• _out/ confirmed gitignored and absent from git status.
• mypy clean; pytest 2717 passed, 1 skipped.

🤖 Generated with Claude Code