Remove coq-lsp and exclude unsupported Mason backends

[segoon]

Summary

• update the data submodule to remove the coq_lsp catalog entry
• remove the coq/coq_lsp E2E pair while retaining the Coq language fixture and vsrocq support
• classify Mason packages using unsupported LuaRocks, Open VSX, OPAM, Composer, and RubyGems backends as explicit provisioning exclusions
• exclude sqruff and standardrb because Mason now classifies them as formatter/linter packages rather than LSP packages
• update pinned compatibility inventory counts

Depends on segoon/lsp-cli-data#7. Merge that PR with a merge commit so submodule commit 8615ebd6d13487114222386fe395ad7707f872ed remains reachable.

Root cause

The E2E planner resolved every server marked downloadable against the current Mason registry. coq_lsp uses pkg:opam, but lsp-cli supports only cargo, generic, github, golang, npm, nuget, and pypi. Auditing the full inventory exposed additional unsupported backends and two packages no longer categorized as LSP packages.

Decisions and tradeoffs

• Pro: the generated workflow matrix now reflects only servers lsp-cli can actually install, while explicit server-level reasons remain visible in the workflow report.
• Pro: unknown future Mason families still fail loudly instead of silently reducing coverage.
• Con: 19 unavailable smoke-pair declarations are removed and remain reported only through provisioning exclusions.
• Alternative rejected: adding OPAM only to the planner would move the failure into the production installer.
• Alternative rejected: silently skipping unknown families would hide coverage loss.

Validation

• cargo test --locked -q: 378 passed, 4 ignored
• live all-selector E2E planner: succeeded with 244 shards across cargo, generic, github, golang, npm, nuget, and pypi
• make test: formatting, tests, Clippy, and README checks passed; cargo deny then stopped on pre-existing RUSTSEC-2026-0285 for rustls 0.23.40, which requires 0.23.45 or newer and is intentionally outside this PR