docs: collect the silent-failure rules into one section

[prorochestvo]

CLAUDE.md states its own job in its second paragraph: the map, plus the rules whose
violation is silent. The second kind was scattered across Architecture Overview,
Key Patterns, HTTP surface, Database, Deployment and Error Handling — a sentence or
two at a time, mixed in with material that announces itself perfectly well. Someone wanting
to know what fails quietly had to read the whole file and judge every paragraph.

They now sit under one ## Tripwires heading, grouped by the skill that carries their
reasoning:

• Collection — egress direct by default, never widen daily, the shared-URL batching.
• Storage — the Transaction / ReadOnlyTransaction split, tiering, weather_forecast_days
  versus the 48 h sweep, the two columns that look droppable, the cascade, the schema gate.
• HTTP — the inner-mux bypass, header-only initData, 404-never-403, and the three
  assertions a controller error test owes.
• Startup ordering, and there is no staging.

Everything that does report itself moved to ## Architecture (the binary map, the layer
table, routes, the health endpoints, the SQLite engine line) or ## Configuration (env vars,
deployment layout).

This is the shape #140 proposed. Its own version could not be rebased through the day's
merges, so the structure is re-derived here over current content — which #140's was missing
entirely, having branched before the outlook work.

Nothing dropped

Text is moved rather than rewritten wherever it survives, so most of the diff reads as
relocation.

backticked spans in the previous file: 191   still present: 190
figures:                                15   still present:  15

The single casualty, named rather than waved off: the spelling `/api/v1/me/...`,
normalised to `/api/v1/me/*` — the form the file already used in the other four places
it appears.

Also fixed on the way through: two code spans (`make init`, `make deploy-configs`)
were broken across a newline by the previous pass's rewrapping. A check that no span crosses a
newline now returns zero.

17823 → 17234. The saving is incidental — the file was already 2177 under budget, and the
point of this change is that the tripwires are findable, not that they are shorter.

scripts/lint-checks.sh clean. Docs only.

Refs #140