find_file and find_type fuzzy scoring: short common substrings rank above exact filename/prefix-stripped matches

## Summary

`find_file` and `find_type` (fuzzy) fail to return correct results for short, common names like `Pawn` and `Actor`. The actual exact-match files/types are completely absent from results because incidental substring matches within longer names (e.g., "pawn" inside "Spawner") receive equal or higher scores and fill all result slots.

## Reproduction

### `find_file` — exact filename missing from results

**Search:** `find_file(filename="Pawn.h", project="Engine", maxResults=10)`

**Expected:** `Engine/Runtime/Engine/Classes/GameFramework/Pawn.h` as the top result (exact filename match).

**Actual:** 10 BlueprintNodeSpawner files (all score 0.71). The actual `Pawn.h` is completely absent:
```
Engine/Editor/BlueprintGraph/Classes/BlueprintAssetNodeSpawner.h (0.71)
Engine/Editor/BlueprintGraph/Classes/BlueprintBoundEventNodeSpawner.h (0.71)
Engine/Editor/BlueprintGraph/Classes/BlueprintBoundNodeSpawner.h (0.71)
...
```

These match because "Spawner" contains "pawn" as a substring: S-**p**-**a**-**w**-**n**-e-r.

**Same issue with `Actor.h`:**

`find_file(filename="Actor.h", project="Engine", maxResults=10)` returns `DatasmithFacadeActor.h`, `ApproximateActors.h`, etc. — all at score 0.71. The actual `Engine/Runtime/Engine/Classes/GameFramework/Actor.h` is absent.

**Works for longer/unique names:** `find_file(filename="DiscoveryHealthComponent", project="Discovery")` correctly returns the right file at 0.7.

### `find_type` — prefix-stripped match lost in substring noise

**Search:** `find_type(name="Pawn", fuzzy=true, project="Engine", maxResults=10)`

**Expected:** `APawn` as a top result (prefix-stripped exact match: `A` + `Pawn`).

**Actual:** 10 Spawn-related types, APawn is completely absent:
```
FAITestSpawnInfoBase (0.91, substring)
FPendingDelayedSpawn (0.91, substring)
FAITestSpawnSetBase (0.91, substring)
FDelayedVisualizerSpawner (0.91, substring)
FNodeSpawnData (0.91, substring)
...
```

**Note:** Exact search `find_type(name="APawn")` works correctly — this is specifically a fuzzy scoring issue.

**Contrast with working fuzzy searches:** `find_type(name="Health", fuzzy=true, project="Discovery")` correctly ranks the exact namespace "Health" at 1.03 and prefix-stripped `UHealthComponent` at 0.98.

## Root Cause

The scoring doesn't differentiate between:
- **Meaningful match:** The filename/type IS the search term (exact or prefix-stripped) — e.g., `Pawn.h`, `APawn`
- **Incidental substring:** The search term appears buried inside a different word — e.g., "pawn" inside "S**pawn**er"

Short search terms (4-5 chars) like "Pawn" and "Actor" are especially affected because they commonly appear as substrings within longer unrelated words.

## Suggested Fix

A word-boundary or whole-word bonus in the scoring algorithm would likely fix both issues. For example:
- If the search term matches a complete word/segment in the filename (delimited by path separators, underscores, or PascalCase boundaries), it should score significantly higher than a substring match within a word.
- `Pawn.h` matching `Pawn.h` (whole filename) >> `BlueprintNodeSpawner.h` (substring within "Spawner")
- `Pawn` matching `APawn` (prefix-stripped) >> `FAITestSpawnInfoBase` (substring within "Spawn")

## Environment

- Tested: 2026-02-08
- All other tools (`find_member`, `grep`, `find_asset`, `find_children`, `browse_module`, `list_modules`) have correct scoring behavior.