ISP indicator hardening, host-side unit tests, PR/push CI

[floesche]

Stacked on #26 (base: mreiser/isp-progress-indicator): review fixes for the visual ISP indicator, plus the repo's first host-side unit tests and PR CI.

Behavior fixes

• Retire moved out of the reply-critical path. Isp::notify_host_command() is now called after panel_spi_arm_confirmation(), so the one-time LittleFS flash erase (tens of ms, core 1 parked via idleOtherCore()) cannot delay the CIPO confirmation of the command that triggered it. Residual quirk, documented in the code: the erase can still stall the next transaction, so bring-up tooling should send a throwaway display command after an ISP flash before starting a stream.
• ERROR_DISPLAY (0xC2) no longer retires the smiley flag. Only content commands count; the filter is the shared retires_boot_indicator() predicate.
• kNominalPages 512 -> 576. A 140 KB image (~547 pages) previously wrapped the bar back to 1 column right before COMMIT; the largest real images now reach 19/20 columns with no wrap.
• Failed ISP_COMMIT shows a sad smiley (status 8, no reboot follows) instead of leaving the full progress bar, which read as success at a glance.
• WRITE_PAGE index clamp. Bounds are checked on the 24-bit page index itself; idx * 256 can no longer wrap uint32 and slip past the staging limit.

Tests + CI

• src/isp_logic.h (new): Arduino-free pure logic (staging constants, bar fill math, retire filter, both face glyphs), shared by isp.cpp, messenger.cpp, and the tests. protocol.h drops its unnecessary <Arduino.h> include so it compiles host-side.
• test/test_isp_logic/ (new): 14 Unity test cases covering bar monotonicity, full-at-nominal, no-wrap for real image sizes, wrap behavior past nominal, the bounds check (including the wrap-index regression), the retire filter over every opcode, and glyph well-formedness/symmetry. Run with pixi run test (= platformio test -d panel -e native).
• .github/workflows/ci.yml (new): runs the unit tests and the pixi run release catalog build on every PR and push to main, using the same pixi-locked toolchain as release.yml.
• Note: the native tests use the system C++ compiler. conda-forge's cxx-compiler bakes the env prefix into its link inputs and breaks on the space in this repo's checkout path ("Generation 6"); documented in pixi.toml.

Validation

• pixi run test: 14/14 pass.
• All 10 firmware envs rebuild clean: pixi run release, pixi run diag, plus explicit builds of the four bcmtest/spidiag envs (the diag catalog does not include them).
• Hardware re-check for flashing single panels and batch of 20 panels worked well

[Copilot]

Pull request overview

Hardens the panel’s visual ISP programming indicator behavior (progress bar + post-flash smiley), extracts Arduino-free ISP logic for host-side testing, and adds PR/push CI to continuously run those tests and build the firmware catalog.

Changes:

• Moves boot-indicator “retire” work out of the reply-critical path; adds sad-smiley on failed commit; clamps WRITE_PAGE indices to prevent offset wrap.
• Adds panel/src/isp_logic.h (pure logic shared by firmware + native unit tests) and introduces host-side Unity tests via PlatformIO native env.
• Introduces GitHub Actions CI running pixi run test and pixi run release on PRs/pushes.

Reviewed changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
pixi.toml	Adds a pixi run test task to run native PlatformIO unit tests.
pixi.lock	Updates lockfile metadata (virtual packages) consistent with new pixi usage.
panel/test/test_isp_logic/test_main.cpp	Adds host-side Unity tests covering ISP indicator math, bounds checks, retire filter, and glyph validity.
panel/src/protocol.h	Removes Arduino dependency to allow host compilation (tests) while keeping protocol constants available.
panel/src/messenger.cpp	Retires the post-flash indicator only after arming the SPI confirmation to avoid delaying the current transaction.
panel/src/main.cpp	Calls Isp::boot_indicator_check() once at runtime (loop) so LittleFS ops happen after both cores are active.
panel/src/isp.h	Exposes boot-indicator APIs and includes shared isp_logic.h.
panel/src/isp.cpp	Implements progress bar + smiley/sad-smiley behavior; adds safe WRITE_PAGE bounds check and host-command retirement logic.
panel/src/isp_logic.h	New Arduino-free shared logic/constants for indicator behavior and bounds checking.
panel/platformio.ini	Adds a native env for host-side unit tests (Unity).
.github/workflows/ci.yml	Adds PR/push CI job running unit tests and catalog build via pixi.

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