Replace Priority and Fairness diagrams with poller-flow flowcharts (#4517)

* Replace Priority diagram with poller-flow flowchart

New diagram illustrates how a poller traverses priority queues from
P1 (highest) to P5 (lowest) and dispatches the first available task,
which conveys the dispatch model more directly than the previous
illustration. Also updates alt text to describe the flowchart content.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Replace Fairness diagram with poller-flow flowchart

Mirrors the Priority diagram's poller-polling structure and surfaces
the backlog-only behavior up front: poller checks for backlog, and
only then does the weighted virtual-queue selection apply.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Update all three priority-fairness diagrams with mermaid renders

- priority-details.png: 5 priority levels with red→yellow→green→blue→
  purple Holocene palette
- fairness-details.png: weighted virtual queue selection with orange/
  pink/cyan tier palette
- priority-fairness.png: combined diagram showing Fairness operating
  within each priority bucket

Also updates the combined-diagram alt text to describe the flowchart
content rather than the prior placeholder.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Add inheritance flowchart to Inheritance subsection

Visualizes the field-resolution cascade: Task Queue weight override
(fairness_weight only) -> explicit value -> inherit from calling
Workflow -> default. Complements the existing precedence chain prose.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* chore(priority/fairness): updated images to be friendly in light-mode and dark-mode

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: flippedcoder <milecia.mcgregor@aol.com>
Co-authored-by: Milecia McG <47196133+flippedcoder@users.noreply.github.com>

Author: 3 people

docs/develop/task-queue-priority-fairness.mdx

@@ -29,7 +29,7 @@ You can use Priority and Fairness individually or combine them to express Fairne
 
 <EnlargeImage
   src="/img/develop/task-queue-priority-fairness/priority-details.png"
-  alt="Detailed view of how Priority works"
+  alt="Flowchart of how Priority dispatches Tasks from highest to lowest priority queue"
 />
 
 ### When to use Priority
@@ -250,7 +250,7 @@ To use Fairness, you need to set fairness keys and optionally fairness weights a
 
 <EnlargeImage
   src="/img/develop/task-queue-priority-fairness/fairness-details.png"
-  alt="High-level of how fairness works"
+  alt="Flowchart of how Fairness selects a virtual queue weighted by fairness weight when the backlog has Tasks"
 />
 
 You can set a Workflow's fairness key and weight via the CLI like so:
@@ -521,13 +521,18 @@ When you use Priority and Fairness together, Priority determines which "sub-queu
 
 <EnlargeImage
   src="/img/develop/task-queue-priority-fairness/priority-fairness.png"
-  alt="High-level of how priority and fairness work together"
+  alt="Flowchart of how Priority and Fairness combine: poller checks priority levels in order, then within each level Fairness selects a virtual queue weighted by fairness weight"
 />
 
 ### Inheritance
 
 Each field of Priority (`priority_key`, `fairness_key`, `fairness_weight`) is resolved independently.
 
+<EnlargeImage
+  src="/img/develop/task-queue-priority-fairness/inheritance.png"
+  alt="Flowchart of how a Priority field is resolved: check for a Task Queue weight override (fairness_weight only), then an explicit value, then inherit from the calling Workflow, otherwise use the default"
+/>
+
 **Activity inheritance order** (highest precedence first):
 
 1. [Fairness weight overrides](#fairness-weight-overrides) on the Task Queue (`fairness_weight` only)