Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@crates/cli/src/outline/extract.rs`:
- Around line 140-170: Replace the unbounded mpsc::channel() call on line 140
with a bounded channel by using mpsc::channel(capacity) instead, where capacity
is an appropriate limit for the maximum number of OutlineFile items that should
be queued. This will apply backpressure to the producer thread when the queue
reaches capacity, preventing memory spikes when parallel walks generate files
faster than the sequential processing loop can consume them. The rest of the
producer and consumer logic using tx.send() and rx.recv() will automatically
handle the bounded behavior.

In `@crates/outline/src/default_rule.rs`:
- Around line 7-726: Add new pattern-based rules to the DEFAULT_OUTLINE_RULES
constant to handle async functions that are currently missing from extraction.
Create rules for async function variants (pub async fn, async fn) that mirror
the existing synchronous function rules such as rust-function-public,
rust-function, rust-function-public-return, rust-function-return,
rust-function-public-generic, rust-function-generic, and their variants with
return types and where clauses. Each async rule should have a unique id prefixed
with rust-async- and patterns that include the async keyword before fn, for
example pub async fn $NAME($$$ARGS) { $$$BODY } and async fn $NAME($$$ARGS) {
$$$BODY }, along with corresponding variants for generic parameters, return
types, and where clauses to match the coverage provided by existing non-async
rules.