refactor(fspy): carry paths inside access variants

[wan9chi]

Motivation

fspy may later track accesses that touch more than one path, such as a rename from one path to another. A record of one path plus one mode can't express that, and neither can consumers that keep a map from path to mode.

Changes

• PathAccess is now an enum whose variants hold their own paths: Read(path), Write(path), ReadWrite(path), ReadDir(path). An access with two paths becomes one more variant. The wire bytes don't change: a one-byte tag, then the path.
• PathAccess::paths() yields every path an access touched, for checks like "did anything touch this path".
• Consumers work on accesses instead of path-to-mode maps:
  • TrackedPathAccesses matches on each variant.
  • The test helper takes the expected variant: assert_contains(&accesses, path, PathAccess::Read).
  • fspy_e2e writes one line per distinct access.
• AccessMode is no longer sent and stays only at the clients' open entry points, where an interception chooses the kind before the path is resolved. AccessMode::with_path builds the record. Exec resolution reports plain paths, and fspy re-exports IpcPath instead of AccessMode.

🤖 Generated with Claude Code

[github-actions]

fspy benchmark

linux

dynamic/launch             change  +0.20%  [ -5.39% ..  +5.61%]  overhead   +52.24%
dynamic/access             change  +0.00%  [ -7.30% ..  +6.64%]  overhead   +23.96%
dynamic/access-relative    change  +0.00%  [ -7.46% ..  +9.08%]  overhead   +72.64%
dynamic/access-contended   change  -0.11%  [-11.06% ..  +9.68%]  overhead   +25.15%
static/launch              change  +0.86%  [ -5.76% ..  +7.67%]  overhead  +180.96%
static/access              change  +1.07%  [ -3.32% .. +17.02%]  overhead +1452.12%
static/access-relative     change  +0.07%  [ -2.13% ..  +2.27%]  overhead +1911.12%
static/access-contended    change  +0.71%  [ -0.75% ..  +1.59%]  overhead +1556.15%

macos

dynamic/launch             change  -0.12%  [ -3.02% ..  +2.78%]  overhead  +225.56%
dynamic/access             change  +1.07%  [ -3.74% ..  +4.85%]  overhead    +3.47%
dynamic/access-relative    change  -0.11%  [ -2.21% ..  +1.91%]  overhead  +259.57%
dynamic/access-contended   change  -0.56%  [ -7.84% ..  +3.74%]  overhead    +2.85%

windows

dynamic/launch             change  +0.02%  [-10.71% ..  +9.39%]  overhead   +26.21%
dynamic/access             change  -0.53%  [-19.78% .. +23.23%]  overhead    +4.11%
dynamic/access-relative    change  -0.25%  [ -5.90% ..  +6.62%]  overhead    +2.14%
dynamic/access-contended   change  -0.92%  [-13.90% ..  +4.34%]  overhead    +3.29%