fix(lsp): restore work-done progress

[fcoury-oai]

Why

Language servers such as rust-analyzer only emit work-done progress after the client advertises support and acknowledges window/workDoneProgress/create. Red advertised progress as unsupported and rejected creation requests, so the bundled Fidget overlay loaded successfully but never received anything to display.

What changed

• Advertise window.workDoneProgress in Red's LSP initialization capabilities.
• Acknowledge server-initiated progress-token creation with a successful JSON-RPC response.
• Replace the obsolete negative capability assertion with a behavioral regression covering initialization, token creation, and begin/report/end notifications for both string and numeric tokens.

How to Test

1. Run cargo test -p red --lib work_done_progress_is_negotiated_created_and_forwarded -- --nocapture. Expect the complete progress handshake and both token variants to pass.
2. Run cargo test -p red --lib fidget_. Expect the bundled Fidget overlay rendering, numeric-token handling, and timer-cleanup tests to pass.
3. Open a Rust project with cargo run -- path/to/src/main.rs. During rust-analyzer indexing, expect the Fidget progress overlay to show the active task and clear after completion.

Validated with cargo clippy --all-targets --all-features -- -D warnings and 2,974 passing package tests. The package run excluded the unrelated pre-existing Neo-tree test neotree_renders_deep_mostly_clean_workspaces_within_the_instruction_budget, whose stale 200-row expectation conflicts with the newer unbounded-tree implementation.