feat: discover jitdump files

[DaniPopes]

Jitdump discovery was hardcoded to /tmp/jit-{pid}.dump, missing dumps from LLVM ORC JIT (e.g. revmc, Julia) which write to ~/.debug/jit/*/jit-{pid}.dump.

Instead of searching hardcoded filesystem paths, extract jitdump file paths from MMAP2 records in the perf data, matching how perf inject --jit discovers them via jit_detect().

[greptile-apps]

Greptile Summary

This PR discovers jitdump files from perf MMAP2 records instead of relying only on fixed paths. The main changes are:

• Adds MMAP2-based jitdump path detection for jit-<pid>.dump files.
• Deduplicates discovered jitdump paths per process.
• Restores the legacy /tmp/jit-{pid}.dump fallback for tracked processes.
• Threads the discovered path map through perf symbol and unwind harvesting.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
src/executor/wall_time/profiler/perf/jit_dump.rs	Adds the shared jitdump path map, per-process deduplication, legacy /tmp fallback, and path-set harvesting.
src/executor/wall_time/profiler/perf/parse_perf_file.rs	Collects jitdump paths from MMAP2 records and accepts jit-<digits>.dump basenames.
src/executor/wall_time/profiler/perf/mod.rs	Passes discovered jitdump paths through the save pipeline and adds legacy fallback paths before harvesting.
Cargo.toml	Adds indexmap as a direct dependency for stable path deduplication.
Cargo.lock	Updates the lockfile for the direct indexmap dependency.

_{Reviews (2): Last reviewed commit: "fix: dedupe jitdump paths" | Re-trigger Greptile}

[not-matthias]

Hey, it looks like the jitdump implementation was only done for the Walltime executor. As mentioned on Discord, we're currently in the process of switching to samply, so this change isn't really needed.

Instead, the jitdump saving should be handled in src/executor/valgrind/executor.rs. Let me know if you have any questions.

[DaniPopes]

woops