Add the circuit-unpacking applicative bootloader's hints

[YairVaknin-starkware]

Implements the hints of the circuit-unpacking applicative bootloader and its circuit-tree unpacker (starkware/cairo/bootloaders/circuit_applicative_bootloader/, added on the main-repo side):

• Input loading and per-run setup: LOAD_CIRCUIT_APPLICATIVE_BOOTLOADER_INPUT, CIRCUIT_APPLICATIVE_SETUP_VERIFIER_RUN (single-task simple bootloader runs for the aggregator and the circuit verifier, saving/restoring the applicative output builtin state), and CIRCUIT_APPLICATIVE_SETUP_UNPACK (builds the unpacker's supported-roots config in Cairo memory and enters the packed-output root node scope).
• The unpacker's node hints (CIRCUIT_UNPACK_*): tree navigation via nested node scopes, leaf data reveal, nine-bit limb splitting, and SET_ROOT_INDEX — each packed node carries its proof's preprocessed root, which the hint locates in the supported-roots list (read back from Cairo memory, matched across all eight words), keeping the hints role-agnostic.
• CIRCUIT_APPLICATIVE_WRITE_FACT_TOPOLOGY: the final fact topology (the aggregator's, page 0 resized for the removed tasks output and the added two-felt header).

The wire types mirror the recursive tree prover's: PackedNode (externally tagged, one node per hash layer, see proving-utils #392) and CircuitApplicativeBootloaderInput. All hints are unit-tested; the full flow is exercised by the main-repo bootloader flow test.

Stack (3/3): aggregator scope var (#393) ← mock verifier hint (#394) ← this.

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This change is 

[cursor]

PR Summary

Medium Risk
Changes affect proof output layout (fact topologies, output builtin pages) and trust anchoring via supported preprocessed roots; mistakes could break verifier runs or produce incorrect GPS facts, though behavior is heavily unit-tested and mirrors existing applicative-bootloader patterns.

Overview
Adds Rust hint handlers for the circuit-unpacking applicative bootloader and its circuit-tree unpacker, wired through codes.rs, hint_processors.rs, and new scope/types (CircuitApplicativeBootloaderInput, PackedNode, CIRCUIT_APPLICATIVE_BOOTLOADER_INPUT).

Bootloader flow hints load program input and orchestrate phased runs: aggregator-only simple bootloader (output segment + saved applicative output builtin state), verifier-only run (stash aggregator fact topologies, switch output segment), unpack setup (restore output builtin, lay out tasks output + supported-roots config in VM memory, enter root PackedNode scope), and final fact topology (resize aggregator page 0 for removed tasks output vs. a two-felt header, configure output pages, optional JSON dump).

CIRCUIT_UNPACK_* hints walk the packed tree via nested scopes: leaf vs internal node, subtask enter/exit, full 8-word Blake2s root lookup in config memory for root_index, leaf preimage segments from decimal felts, and 28×9-bit limb splitting for felts.

Extensive unit tests cover happy paths, malformed nodes/roots, missing ids, and fact-topology edge cases; MOCK_CIRCUIT_VERIFIER_LOAD_INPUT is regrouped with the other circuit hint constants.

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[codecov]

Codecov Report

❌ Patch coverage is 98.70436% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.24%. Comparing base (4fb6a87) to head (1c1713b).

Files with missing lines	Patch %	Lines
...ro-program-runner-lib/src/hints/hint_processors.rs	57.89%	8 Missing ⚠️
.../src/hints/circuit_applicative_bootloader_hints.rs	99.63%	3 Missing ⚠️

Additional details and impacted files

@@                           Coverage Diff                            @@
##           yairv/add_mock_circuit_verifier_hint     #395      +/-   ##
========================================================================
+ Coverage                                 68.42%   72.24%   +3.82%     
========================================================================
  Files                                        42       42              
  Lines                                      6011     6860     +849     
========================================================================
+ Hits                                       4113     4956     +843     
- Misses                                     1898     1904       +6     

Files with missing lines	Coverage Δ
crates/cairo-program-runner-lib/src/hints/types.rs	71.06% <ø> (ø)
.../src/hints/circuit_applicative_bootloader_hints.rs	99.68% <99.63%> (-0.32%)	⬇️
...ro-program-runner-lib/src/hints/hint_processors.rs	62.91% <57.89%> (-0.34%)	⬇️

... and 2 files with indirect coverage changes

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[OmriEshhar1]

@OmriEshhar1 partially reviewed 4 files and made 1 comment.
Reviewable status: 4 of 5 files reviewed, 1 unresolved discussion (waiting on Gali-StarkWare and YairVaknin-starkware).

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crates/cairo-program-runner-lib/src/hints/types.rs line 571 at r3 (raw file):

/// (the leaf's hashed output and each fold's circuit output) bottom-up from the preimages.
#[derive(Debug, Clone, PartialEq, Deserialize)]
pub enum PackedNode {

enum PackedNode already appears in stwo_run_and_prove_recursive_tree crate.
isn't there a shared location where you can define it?
(is this temporary until you'll merge both PR stacks?)

[OmriEshhar1]

@OmriEshhar1 reviewed 1 file and all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on Gali-StarkWare and YairVaknin-starkware).

[YairVaknin-starkware]

@YairVaknin-starkware made 1 comment.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on Gali-StarkWare and OmriEshhar1).

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crates/cairo-program-runner-lib/src/hints/types.rs line 571 at r3 (raw file):

Previously, OmriEshhar1 wrote…

enum PackedNode already appears in stwo_run_and_prove_recursive_tree crate.
isn't there a shared location where you can define it?
(is this temporary until you'll merge both PR stacks?)

Yes, basically until the first is merged. Didn't want to build 2 stacks on a commit that isn't on main.

[OmriEshhar1]

@OmriEshhar1 resolved 1 discussion.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on Gali-StarkWare).