docs: setup files and the client, shared and CI docs describe what is (#6277)

.dockerignore, .gitignore, deploy/initdb, ci-requirements.md,
client/README.md, shared/README.md and two web/scripts test names: dates,
issue/rule/spike ids and the stories behind each exclusion removed.

Corrected:
- client/README.md: the dev lane bundles its own APK; :main no longer
  exists; main bundles the recorded sidecar instead of re-deriving the
  version name. Its smoke-test step wrote a bare "v0.2.0", which the
  server rejects as a sidecar that is not JSON; it now writes the JSON
  shape, which the README documents.
- ci-requirements.md: one workflow, not four; the android lane builds no
  debug APK; main reads the recorded sidecar.
- .gitignore: CI fills client/ on every image build, not tag releases only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

deploy/initdb/01-create-test-db.sql

@@ -1,6 +1,5 @@
 -- Runs once, only on a fresh Postgres data volume (Docker entrypoint
 -- initdb hook). Creates the dedicated integration-test database so
--- `go test` never truncates the operator's dev `minstrel` DB (Fable
--- #339). For an already-initialised volume this script does NOT run;
+-- `go test` never truncates the dev `minstrel` DB. For an already-initialised volume this script does NOT run;
 -- `make test-integration` creates the DB idempotently instead.
 CREATE DATABASE minstrel_test OWNER minstrel;