fix(files): prune dependency dirs in expandFileGlobs before fast-glob traversal - #410

In getEffectivePrunePatterns, the negation check neg.includes(${dirName}/) || neg.includes(/${dirName}) is an unbounded substring test, so a user negation whose directory name merely starts with a prune name removes the wrong prune entry. For example !src/output/** drops **/out/** (since /output contains /out), and !builder/** drops **/build/**, so that build/output tree is no longer pruned at traversal time and can be fully enumerated—reintroducing the memory pressure / WardenGlobExpansionError the prune list exists to prevent.

Also found at:

• packages/warden/src/cli/files.test.ts:140-143
• packages/warden/src/cli/files.ts:268
• packages/warden/src/cli/files.ts:403

The guard files.length >= MAX_GLOB_FILE_RESULTS throws WardenGlobExpansionError when a project matches exactly 10,000 files, but the class docstring says it is thrown only when expansion returns "more than MAX_GLOB_FILE_RESULTS candidates" and the error message states "limit is 10,000". A legitimate project with exactly 10,000 source files is rejected with the self-contradictory message; use > to match the stated semantics.