feat: add OpenWiki project memory

[ousamabenyounes]

Summary

• add opt-in, pinned openwiki@0.5.1 installation through --with-openwiki, and include it in --all
• keep repository initialization explicit: installation never runs openwiki --init
• strongly recommend OpenWiki as shared, Git-versioned project memory for active team projects
• document the complementary Graphify/OpenWiki workflow and regular graphify update . / openwiki --update refreshes
• replace the long README with a short documentation menu and focused pages
• make provider tests hermetic so network update state cannot make the Copilot assertion flaky

Why

OpenWiki generation has an upfront LLM cost, but the resulting grounded Markdown is reused by every contributor, session, and agent. On long-lived team projects, that amortizes repository-understanding work instead of paying to rediscover the same architecture repeatedly. Graphify remains the fast structural index; OpenWiki becomes the durable shared explanation layer.

Installation behavior

bash install.sh --with-openwiki
bash install.sh --all

Both install the pinned CLI. Neither initializes or scans the current repository. Project owners deliberately run openwiki --init once in the intended repository, then openwiki --update after meaningful merged changes. A clean no-op update makes no LLM call.

Validation

• ShellCheck at CI warning threshold: pass
• full Bats suite: 192/192 pass
• new OpenWiki installer coverage: pinned standalone install, no implicit init, and --all inclusion
• Markdown relative-link validation: 8 files pass
• bash -n install.sh: pass
• bash install.sh --help: pass
• git diff --check: pass

Estimate and actuals

• pre-implementation estimate: 45–90 minutes; 35k–90k tokens; $0.05–$0.50 API-equivalent
• measured elapsed wall time: 7h 33m 25s, including idle time and CI/test waits
• active engineering time: unavailable from this execution surface
• actual input/output/cache tokens and provider cost: unavailable from this execution surface, so they are not fabricated

No database, API, Alembic, Swagger, or application validation-page change applies to this shell-and-documentation repository change.