chore(workspace): Reduce target directory bloat

[refcell]

Description

Changes split-debuginfo from "unpacked" to "packed" and disables incremental compilation in dev profile.

Why

The target/ directory grows unboundedly over time (200GB+) due to:

1. Unpacked debug info creates thousands of loose .o/.dwo files that accumulate
2. Incremental compilation cache retains ~20+ versions of build artifacts with no garbage collection

Tradeoffs

• Slightly slower rebuilds without incremental compilation (~15-20% overhead on from-scratch builds)
• Debug info still available, just bundled into binaries instead of separate files

[cb-heimdall]

✅ Heimdall Review Status

Requirement	Status	More Info
Reviews	✅ 1/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 1 Sum 2