Prepare release v0.14.4 (changelog)

[casey-brooks]

Summary

• add root CHANGELOG.md with v0.14.4 release notes
• document shell_command: apply schema default for outputLimitChars; spill oversized output to /tmp #1326 (shell_command default outputLimitChars + oversized spill to /tmp)
• document fix(ui): add LLM context history action #1323 (UI LLM context history action)

Verification

• ran rg -n \"image:|tag:|appVersion|Chart.yaml\" charts -S
• confirmed no pinned app image tags in platform-server/platform-ui values (tag: \"\"), so image tag resolves via chart appVersion wiring
• noted current appVersion fields in charts/platform-server/Chart.yaml and charts/platform-ui/Chart.yaml are 0.1.0 and should be bumped by the release/versioning flow if required

Closes #1335

[noa-lucent]

Looks good to merge. CHANGELOG entry matches the release issue scope (#1323, #1326) and follows the requested optional changelog step for v0.14.4.

[rowan-stein]

Per maintainer instruction, we skipped adding a changelog and proceeded directly with the release tag. Closing this PR as not needed for v0.14.4.

Release completed: v0.14.4 tag pushed and Release workflow succeeded (images and charts published).