fix: make the hub installable outside its repo root

[CodeWithJuber]

Three things blocked installing this hub globally into MCP hosts.

1. Specs were unreachable from any working directory but the repo root

build_catalogue() and validate both did Path::new("specs"). MCP hosts launch stdio servers with an arbitrary cwd, so the server started with zero providers and no error — list_providers just returned an empty array.

Specs are now resolved in order:

1. CONNECTOR_HUB_SPECS_DIR — explicit override
2. ./specs — repo-root invocation, unchanged behaviour
3. specs/ found by walking up from the executable — covers crates/target/release/connector-hub

2. Both plugin manifests pointed at files that did not exist

.claude-plugin/plugin.json and .codex-plugin/plugin.json declare "mcpServers": "./.mcp.json" and "skills": "./skills/". Neither path existed in the repo, so neither plugin could load. Added:

• .mcp.json — uses ${CLAUDE_PLUGIN_ROOT} and sets CONNECTOR_HUB_SPECS_DIR explicitly, which only works because of fix 1
• skills/connector-hub/SKILL.md — search → describe → dry-run → call workflow, how to read the five execution states, and the rule that a non-Succeeded state is never "probably worked"

3. Manifest counts were stale

All four manifests advertised 21 providers / 278 operations. The catalogue has been 24 / 301 since the ops connectors landed — README.md already said so. Synced and bumped to 2.1.0 (parity check in validate still passes).

Also

hub-net/src/client.rs had a collapsible_match that fails cargo clippy --all-targets -- -D warnings on Rust 1.95+, which is what CI runs. Collapsed into a match guard; behaviour is identical (a null body on POST/PUT/PATCH still sends no JSON).

Verification

cargo fmt --check                     ok
cargo clippy --all-targets -D warnings  ok
cargo test --workspace                ok (26 tests)
cargo run -- validate                 301 operations, 24 providers, 32 destructive

Confirmed end to end: MCP handshake from a cwd outside the repo returns all 24 providers.

🤖 Generated with Claude Code

https://claude.ai/code/session_018Xs4hZtZhd9Vi6EJnVnwDf