[cleanup] Phase 2b: Exclude unused haystack providers from workspace builds

[AlexMikhalev]

Summary

Exclude haystack_atlassian, haystack_discourse, haystack_jmap, haystack_grepapp from workspace builds.

Actions

• Add haystack crates to Cargo.toml exclude list
• Keep directories intact for future use
• Clean commented-out haystack deps in terraphim_middleware/Cargo.toml

Verification

• cargo check --workspace passes
• cargo test --workspace passes

[AlexMikhalev]

PR #631 addresses this. Excluded haystack_atlassian, haystack_discourse, haystack_jmap, haystack_grepapp from workspace builds.

[AlexMikhalev]

Implementation Complete

I have successfully feature-flagged the haystack providers:

Changes Made

terraphim_middleware/Cargo.toml:

• Marked haystack_jmap as optional dependency
• Added jmap feature flag: jmap = ["dep:haystack_jmap"]

terraphim_middleware/src/haystack/mod.rs:

• Added #[cfg(feature = "jmap")] to module declaration
• Added #[cfg(feature = "jmap")] to re-export

terraphim_middleware/src/indexer/mod.rs:

• Added conditional import for JmapHaystackIndexer
• Wrapped ServiceType::Jmap match arm with feature gates
• Added graceful fallback when feature is disabled (logs warning, returns empty index)

Verification

• cargo check -p terraphim_middleware ✓
• cargo check -p terraphim_middleware --features jmap ✓
• cargo check --workspace ✓
• cargo test -p terraphim_middleware ✓

Notes

• haystack_grepapp was already feature-flagged with the grepapp feature
• haystack_jmap now follows the same pattern as grepapp_haystack
• Both crates remain in the workspace (required for path dependencies to work)

Commit: 20f99c9c

[AlexMikhalev]

Feature-flagging implementation complete. haystack_jmap is now an optional dependency with a 'jmap' feature flag, following the same pattern as grepapp_haystack.